Quote:
Originally Posted by beren
Nice Roger  great effort for the focal length and exposure times {tracking LX200 ?}. Do you check the focus before each exposure or is it automated? Good weather lately in Perth not to hot to get out the gear out  |
It re-focusses every hour, and it's automated. Focus isn't always perfect but tends to be afected more by thin cloud or atmospherics than focus drifting.
Quote:
Originally Posted by gregbradley
That's not bad Roger. Firstly that is a tough target. Those 2 galaxies are very small and you are imaging at over 2.5 metres. SCT's do tend to give larger star sizes and there would be some chromatic aberration from the corrector plate. But the red halo may be coming from registration being a bit off. I use the CCDstack plug in registration and its highly accurate. Perhaps also the red focus is a tad off or the seeing was worse when you did the red. You could lightly deconvolve the red subs to bring the star sizes in line with the other channels.
I don't think NABG has anything to do with it as that causes blooms which I don't see here.
Greg.
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Thanks Greg. I'm glad you say SCT's give larger stars, makes me feel slightly better. Registration was done in CCDStack but when combining the CRGB frames I found it didn't get perfect registration
